Effects of Formaldehyde and Weak Light Stress on Growth and Nutrition of Hedera spp.

In this paper,took the potted seedlings of Hedera nepalensis and H. helix as the experimental materials,set four treatments of formaldehyde,weak light,formaldehyde + weak light and control in airtight glass containers,and measured some morphological and nutritive index,to investigate the effects of formaldehyde and weak light stress on the growth and nutrition of two species of Hedera spp.,and then reveal the adaptability and regulatory mechanisms. The results showed that under formaldehyde or weak light stress,leaf length,leaf width,stem length,stem diameter,root length and biomass of the two species of Hedera spp. decreased,but leaf shape index increased. The formaldehyde stress made root-shoot ratio increased,the weak light and formaldehyde + weak light stress made root-shoot decreased. Under formaldehyde stress,soluble sugar content in roots,stems and leaves of two species of Hedera spp. decreased,and starch content increased; the contents of total carbon and proline and carbon-nitrogen ratio increased,the contents of protein and phosphorus decreased in root; the contents of total carbon,protein and total nitrogen in leaf decreased; carbon-nitrogen ratio in root of Hedera nepalensis increased; the carbon nitrogen ratio of in the root of Hedera nepalensis and the leaves of two species ivy increased significantly.Under the double stress of formaldehyde and weak light,the soluble sugar content decreased,starch content increased in stems and leaves of two species of Hedera spp. and starch content in root decreased; the contents of protein and total nitrogen in leaf of Hedera nepalensis decreased,carbon-nitrogen ratio increased,proline content in root increased significantly. In addition,the content of proline in the roots and stems of two species of Hedera spp.increased significantly under double stress. All the indicators of Hedera nepalensis showed more stable under weak light,and the indicator of H. helix was stable under the formaldehyde stress. And under the weak light of Hedera nepalensis carbon-nitrogen ratio was higher than H. helix,under the formaldehyde stress of H. helix could still be normal growth.